1. Field of the Invention
The instant invention relates generally to dental implants and, more particularly, to a dental implant interface and assembly having an implant portion for securement and osseointegration into an osseotomy site and an abutment portion, securable to the implant portion, for the support of a dental prosthesis.
2. Background and Prior Art
The present invention relates to an improvement over existing spline implant to abutment interfaces as, for example, are reflected in U.S. Pat. No. 5,449,291 (1995) to Lueschen et al, entitled Dental Implant Assembly having Tactile Feedback as well as an improvement of implant/abutment assemblies which employ pin-type interfaces as is reflected in U.S. Pat. No. 5,302,126 (1994) to Wimmer et al, entitled Dental Implant with Adjustable Post. The prior art of Lueschen, and a variant thereof, are shown in FIGS. 1 and 1A. Therein are shown implants 15 and 17 as well as an abutment 19. As may be noted, the male or projecting elements are associated with the implant element, this in distinction to the invention as set forth below, i.e., in which the prongs occur from the abutment, not the implant.
A longstanding concern in the area of implant dentistry has been that of minimizing or eliminating rotation, or the potential therefore, of the abutment portion of the implant system relative to the implant or anchor portion which is embedded within the alveolar bone of the patient. As such, in all implant systems, it is imperative to provide resistance to rotation and, as well, provide for accurate radial, polar and axial indexing of the abutment portion relative to the implant portion. An additional requirement of attachment of the abutment to the implant is termed xe2x80x9ctactile feedback,xe2x80x9d that is, the feeling provided to the hand of the clinician as the abutment is seated with the implant portion. That is, during assembly of the abutment to the implant, it is important for tactile feedback to clearly indicate that the abutment is fully seated in the implant before a securing screw is tightened. As such, implant systems in the prior art that address anti-rotation to the exclusion of tactile feedback will often result in a mis-seating of the abutment relative to the implant. Conversely, systems which are primarily concerned with tactile feedback often result in an implant-to-abutment interface which lacks long-term rotational stability. The instant invention therefore provides an optimization of these otherwise competing objectives in the prior art of abutment-implant interfaces.
The invention relates to a dental implant-abutment interface and assembly comprising an implant, an abutment removably attachable to the implant, and a screw receivable within an axial threaded bore common to both said implant and abutment. More particularly, said implant includes an elongate body having a proximal end and a distal end, said axial threaded bore open at said proximal end, a radial end surface of a collar comprising said proximal end, and a plurality of axially elongate recesses substantially arcuate in radial cross-section, disposed polarly at said proximal end, and extending distally away from said radial end surface. Each of said arcuate recesses exhibit a curved wall, each having a tangent lying on a common circle disposed inwardly of a circumference of said collar of said implant. Said abutment includes said axial threaded bore, a proximal end, and a distal end itself comprising collar and prongs projecting distally away from a radial plane at a distal-most axial extent of said collar in which said radial plane is complementally engagable with said radial end surface of said implant. Said prongs are disposed equipolarly about said axial bore of the abutment, and each of said prongs are proportioned for engagement with a respective one of said axial circular recesses of said implant, said axial bore of the abutment communicating with the axial bore of said implant, and said radial surface of said collar having a like radius to that of said radial end surface of said implant. Each of said prongs has a radial cross-section of lesser area than that of its respective implant circular recess. The axial bore of said abutment is provided with a screw head-engaging internal shoulder upon which a head of the screw rests after the length thereof complementally engages said threaded bore of the implant.
It is an object of the instant invention to provide a dental implant assembly including an implant portion and an abutment wherein the abutment resists rotation relative to the implant and is radially indexable relative thereto.
It is another object to provide a dental implant/abutment interface having prong and circular channel interconnections to both provide accurate indexing and piloting of the abutment prior to full engagement with the implant.
It is a further object of the invention to provide an implant/abutment interface which provides tactile feedback to the clinician while also providing resistance to rotation after osseointegration of the implant into the alveolar bone of the patient.
It is a still further object to obtain an interface and assembly of the above type wherein interconnecting prongs thereof may fail as a result of over-torquing of the abutment without damage to the implant or failure of the implant-abutment interface, and in which indexing of the prongs can be reset within the implant to either continue to screw the implant into the bone or to remove the implant from such bone, thereby providing a fail-safe feature to the implant clinician not withstanding such prong failure
The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings and Detailed Description of the Invention as set forth herein.